I feel a little uneasy about 25209715d44562dcbf26f04ed9e0d19ee3c2aa84. I think ignoring all backend errors in close(), on all backends, may hide real problems. For the purpose of this ticket, 53d97e4fe300f2775b5bb1b8010ec415994fa105 serves the same purpose with much narrower focus; more generally, I think we should only catch connection.features.closed_cursor_error_class -- I don't think we can reasonably say that any other error should be silenced.